Antioxidant Activity of Black Garlic (Allium sativum L.)

The antioxidant activities of hot water and ethanol extracts from fresh, steamed and black garlic were compared. The levels of phenolic compounds of extracts from fresh, steamed and black garlic were 0.81～0.99 ㎎/100 g and their contents were not significantly different. The contents of flavonoids in ethanol extracts, 0.96±0.05～1.06±0.09 ㎎/100 g, was higher than hot water extracts. DPPH radical scavenging activity was higher in ethanol extract. Although the highest level was 69.40±0.13% in concentration of 10 ㎎/mL from black garlic ethanol extract, ethanol extracts showed 50.55±1.40% in concentration of 15 ㎎/mL. Reducing power was significantly higher in black garlic extract and higher in the order of black garlic＞ fresh garlic＞steamed garlic in ethanol extract. Hydroxyl radical scavenging activity was higher in ethanol extract, showing over 60% in concentration of 5 ㎎/mL. In oil emulsion, TBA value was significantly lower in hot water extracts from black garlic, however ethanol extracts were not significantly different. TBA value of ethanol extract were 1.49±0.08～2.11±0.16 MA ㎎/kg and 1.33±0.18～1.62±0.19 MA ㎎/kg from steamed and black garlic, respectively. Antioxidant activity to the linoleic acid was 72.71±2.17～88.74±3.70% in 1-day storage, but its level was increased at 4-day storage to 86.67±3.76～92.50±0.87%.